1. Field of the Invention
This invention relates to an eye pressure meter utilizing the deformation of a cornea which is for use in an ophthalmic hospital or the like.
2. Related Background Art
Heretofore, an apparatus of this type, as is known from U.S. Pat. No. 3,585,849, etc., has detected the quantity of reflected light from a cornea to thereby detect the predetermined deformation of the cornea, thus finding the eye pressure therefrom. Particularly, the apparatus shown in U.S. Pat. No. 3,585,849 is designed to project a light beam from outside the optic axis toward the cornea, detect the quantity of reflected light from the cornea by a photoelectric element disposed outside the optic axis and know a state in which the cornea is pressed flat.
However, in the prior art, the deformation of the cornea has been found by detecting the quantity of reflected light from the cornea and therefore, a measurement error has occurred when the quantity of light of the light source varies during measurement, and to prevent this, the stability of the light source has been required.
Also, measurement has been compelled to be done with the distance in the direction of the optic axis between an eye to be examined and the apparatus, i.e., the so-called working distance, being strictly adjusted.